Fears grow for hunger-striking Ukrainian film director Sentsov

Fears grew Thursday for the health of Ukrainian film director Oleg Sentsov who has declared a hunger strike in a Russian prison, with a politician who spoke to him via videolink saying he appeared unwell and warning "this could end badly".

The 41-year-old went on hunger strike on May 14, demanding that Moscow release all its Ukrainian political prisoners as Russia prepares to host the 2018 World Cup next month.

Sentsov, a pro-Ukrainian activist and documentary director, was detained in Crimea in 2014 after Russia annexed the peninsula. He was accused of masterminding arson attacks.

Sentsov, who denied the allegations, is serving a 20-year sentence in Russia's far north after being convicted on terrorism charges.

Politician and media star Ksenia Sobchak said she spoke to Sentsov in a video call on Thursday and tried to persuade him to halt his hunger strike but he refused.

"I am horrified because I understand that he looks like a man who will go all the way," she told liberal radio Echo of Moscow.

"He is very pale, very thin," she said, adding that his teeth have begun to crumble.

On Monday, Russia's prison service said Sentsov agreed to "receive supportive therapy," without providing further details.

The prison service said his condition was "satisfactory."

Sentsov's lawyer Dmitry Dinze told AFP on Thursday he had no recent contact with his client but was going to visit him on Monday.

He said the director was stable, but confirmed Sentsov had lost two teeth.

"The climate does not agree with him," he said, adding that there was no dentist in his prison so teeth have to be pulled out.

Top opposition leader Alexei Navalny, who is serving a 30-day sentence over organising an illegal protest, called on President Vladimir Putin to release more than 60 "Ukrainian political prisoners" including Sentsov.

"His feat, and his sacrifice, and his death will put him on a par with Bobby Sands, (Anatoly) Marchenko and other titans of humankind," he wrote on his blog, adding Putin should want to avoid this.

Irish nationalist Sands died in prison in 1981 after 66 days on hunger strike, while Soviet dissident Anatoly Marchenko died in prison in 1986 after a three-month-long hunger strike for the release of Soviet prisoners of conscience.